A permanent snow cover for several months is typical for large parts of Norway, Sweden and Finland. Snow layers thicker than about 20 cm insulate the soil surface and stabilize the ground temperature close to 0°C. Many ground-living invertebrates are active at this temperature in the subnivean air space. From this "base camp", some invertebrates migrate upwards to use the snow as a substrate. The intranivean fauna consists of springtails (Collembola) and mites (Acari) that are small enough to move within the narrow pores between snow crystals. The supranivean fauna consists of various invertebrates that are active on the snow surface. Some of them are Collembola that have migrated through the snow layers. However, most of them are larger insects and spiders which migrate between the subnivean and supranivean habitats following air channels which are naturally created along tree stems, bushes etc. penetrating the snow. Likewise, certain Chironomidae and Plecoptera, hatching from winter-open rivers and brooks, are active on the snow surface. The supranivean arthropod fauna has the following characteristics: 1. It is a weather dependent assemblage of species, coming and going with changes in air temperature, cloud cover, and wind. Below ca. -6°C animals are absent, but at temperatures around or above zero, many groups can be simultaneously active on snow. 2. The snow surface fauna shows phenological changes throughout the winter, as certain species and groups are mainly active during certain months. 3. Some invertebrates are highly specialized and take advantage of the snow surface as an arena in their life cycle. Examples are Hypogastrura socialis (Collembola), and the two wingless insects Chionea sp. (Diptera: Limoniidae) and Boreus sp. (Mecoptera). They use the smooth snow surface for efficient migration. Chionea sp. and Boreus sp. lay their eggs during the snow-covered period, while H. socialis migrates to create new colonies. The cold tolerant spider Bolephthyphantes index is unique in constructing webs in small depressions on the snow, to catch migrating Collembola. Various adaptations for using the snow as a substrate are discussed. Besides physiological and morphological adaptations, snow surface arthropods show special behavioural adaptations. Most conspicuous is the ability of several Collembola species to navigate during migration, using the position of the sun for orientation. Furthermore, in Collembola and Mecoptera, jumping as an original mechanism to escape predators has independently evolved into a migrating mechanism. An evolutionary potential exists for more invertebrate groups to take advantage of snow as a substrate in their life cycle. For instance, several more cold tolerant spiders might evolve the ability to catch migrating Collembola on snow.
Only in the southern part of the Iberian Peninsula the large white butterfly Pieris brassicae was recorded to pass the summer in pupal aestivation, induced by long-day photoperiods. It is not clear why this photoperiodic response is regionally restricted. We investigated whether the change of life history in P. brassicae may affect the infestation by parasites. This was done by testing the coincidence of photoperiodic responses in both the host P. brassicae and in its main parasitoid Cotesia glomerata. While the response under short-day conditions was very similar in both species, no summer dormancy of any type was found in the parasitoid at photophases >= 15h and temperatures of 15°-25°C in contrast to 100% aestivation in the host. We suggest that aestivation is a response which allows the host to desynchronise its life cycle from that of its parasitoid. This is effective because parasitoid wasps cannot pass the temporary absence of suitable host stages by a similar developmental rest. C. glomerata is then forced to switch to less adequate host species which diminishes its reproductive success.
The article on the Romani migration from Slovakia to the territory of the Czech Republic is based on the field research realized by the organization „Člověk v tísni" (People in Need) in
the year 2003. Analysis of this probe has shown that the non-asylum Romani migration was in the year 2003 much stronger than the migration of asylum seekers; that in the case of non-asylum migration this was in the first place an innovation migration, while in the case of
asylum seekers it was a so called survival migration. The non-asylum migration was usually a chain migration either of individuals or families and utilises family relations in the country of
origin as well as in the country of final destination. The information is being handed on not only through families, but also in settlements; some of them even specialize in some kind of
migration. The migration of Romani between the Czech Republic and Slovakia is bid-irectional, but more Romani migrate into the Czech Republic then to Slovakia, due to better economic situation there. Romani migration is a dynamic phenomenon and because of its character, based on close family relations of Romani residents on Czech and Slovak territory, it will for sure continue in future.
Arsenic release and its kinetic in severely contaminated stream sediments of the Kyjov brook and impoundment material (eastern Slovakia) using column and batch experiments was studied. The results of the column experiments showed that As release from the solid samples by water was likely controlled by Fe and Mn oxyhydroxides and pH of the sediments and leachates. It was also observed that extraction time was an important factor influencing the As release. The empirical correlations between the rate constants of As release and oxalate-extractable Fe content or total Mn content imply that diffusion in hydrated micropores of amorphous Fe and Mn oxides might be the rate-limiting mechanism of the As release. Although the fractions of As released in column experiments were generally less than 10 % of its total contents, these low fractions represented high absolute amounts of readily available and water-soluble As with a mean value of 83 mg kg-1. This amount of readily available As is approximately 4-times higher than the guideline value for As according to DEFRA UK, based upon ''bioavailable'' concentration, indicating high As availability for plants and living organisms in the studied region. and V štúdii bolo sledované uvoľňovanie arzénu a jeho rýchlosť vo výrazne kontaminovaných riečnych sedimentoch toku Kyjov na východnom Slovensku a materiáli odkaliska použitím kolónových a nádobkových experimentov. Výsledky kolónových experimentov naznačujú, že pravdepodobne najväčší vplyv na uvoľňovanie As vodou majú oxyhydroxidy Fe a Mn a pH výluhov a použitých sedimetov. Ukázalo sa, že aj čas trvania kontaktu kontaminovaných vzoriek s roztokom je dôležitý faktor uvoľňovania As. Nájdené korelácie medzi rýchlostnými konštantami uvoľňovania As a extrahovateľnými obsahmi Fe šťavelanom amónnym ako aj celkovými obsahmi Mn by mohli poukazovať na fakt, že difúzia v hydratovaných mikropóroch amorfných oxyhydroxidov Fe a Mn je hlavný mechanizmus limitujúci rýchlosť uvoľňovania As. Hoci frakcie uvoľneného As v kolónových experimentoch boli celkovo nižšie ako 10 % z jeho totálnych obsahov v skúmaných vzorkách, tieto nízke frakcie predstavujú vysoké obsahy ľahko dostupného a vo vode rozpustného As s priemernou hodnotou 83 mg kg-1. Uvedený obsah ľahko dostupného As je približne 4-krát vyšší ako smernicová hodnota podľa DEFRA UK založená na ''biodostupnej'' koncentrácii As. Toto porovnanie poukazuje na potenciálne vysokú dostupnosť As pre rastliny a živé organizmy v študovanej oblasti
The article describes the establishment and development of Puhoi, a small village in New Zealand known as „Bohemian settlement”, from an anthropological point of view. Puhoi was established in 1863 by settlers who came to New Zealand from Bohemia and who presented themselves as „Bohemians”, however there has been a diversity of opinions on their ethnicity. In this article, we look for the answer to the question of the settlers’ identity and we follow its changes during the process of acculturation in relation to indigenous Maori population as well as during the process of continuing integration into New Zealand’s society. Further, the article examines the surviving tradition together with contemporary marks of distinctiveness and poses a question if Puhoi can still be viewed as unique and different within New Zealand’s culture.
Vegetation on mountains is expected to react in a highly sensitive way to climate change and species losses are predicted in the near future. By means of monitoring studies changes in species diversity can be continuously recorded. In this paper the results of a 7-year study in the Southern Alps are reported. As part of the worldwide network GLORIA (The Global Observation Research Initiative in Alpine Environments) four summits, at altitudes ranging from the treeline to the alpine-subnival ecotone (2199, 2463, 2757 and 2893 m a.s.l.) in the Dolomites (northern Italy) were studied. Sites on the four summits were used to determine the effects of climate warming and observe changes in the numbers of species of vascular plants, frequency and composition. It is hypothesized that ‘thermophilization’ is likely to occur over a period of 7 years (i.e. species from lower altitudes are expected to migrate to the summits due to climate warming). It is also hypothesized that nival, alpine-subnival and endemic species might decrease due to competitive displacement by species from lower altitudes. The summit areas were comprehensively sampled (from the highest point down to the 10 m contour line) in 2001, 2006 and 2008. In addition, 4 × 1 m2 permanent plots located 5 m below the highest summit point on the north, south, east and west sides of each summit were sampled. The results of revisiting the summits indicate that the number of species increased on all four summits, with the greatest gains (15% and 18%) recorded on the two highest summits and moderate gains (4% and 9%) on the two lower summits. Species’ frequencies within the 1 m2 plots also increased during the 2001–2008 period. A thermophilization trend was demonstrated in which species with distribution centres in the montane or tree line zones were found for the first time on three of the summits. On the lowest summit, the vigorous growth of trees and establishment of new saplings indicate an upward migration of the forest boundary. Species that disappeared from the four summits belonged to species with different altitudinal ranges; however, nival and subnival-alpine species remained. One endemic species, Potentilla nitida, disappeared from the highest summit. Further changes and clearer trends are expected in the next decade.
The article deals with the question how EU anti-discrimination law and migration law are inter- related. The concept of fundamental market freedoms and the prohibition of discrimination based on na- tionality have approximated the status of state nationals and Union citizens. General human rights law, on the other hand, has strengthened the legal status of third-country nationals, also in the field of migration law. The combination of both approaches in the light of current anti-discrimination directives and activist human rights jurisprudence may lead to confusion.
Historical data sources on abundance of organisms are valuable for determining responses of those organisms to climate change and coincidence of changes amongst different organisms. We investigate data on the general abundance of Lepidoptera over an 89 year period 1864-1952. We related abundance to monthly mean temperature and precipitation and the winter North Atlantic Oscillation (NAO) index, and to numbers of migrants from an independent source. Abundances of Lepidoptera were significantly positively correlated with current year temperatures for May to September and November and significantly negatively correlated with temperatures in January. Numbers were also negatively correlated with rainfall for April and May and annual total of the current year and with August in the previous year. Abundance of Lepidoptera decreased significantly with an increasing winter NAO index. Increased overall abundance in Lepidoptera coincided significantly with increased numbers of migrants. The climate associations were very similar to those previously reported for butterfly data collected by the British Butterfly Monitoring Scheme; although warm and drier summers were generally beneficial to Lepidoptera populations, wet summers and winters and mild winters were not. We discuss the implications for Lepidoptera biology and populations in regions of Britain in the face of projected climate changes.
The text serves as an example of the multi-sited ethnography within the frame of the migration processes from Central Europe to the Balcans throughout the nineteenth century. It focused on the settlement Clopodia (in Czech, Klopotín) in Rumanian Banat, settled in the middle of the nineteenth century by numerous population from the Czech Lands.